I don't have a T5, but I do have a comparable instrument - the Godin Multiac Spectrum:
Like the T5, it has an acoustic bridge pickup together with an electric pickup next to the fretboard, and the sounds of these two pickups can be blended or separated, according to choice. Recently, I came across some strings called DR Zebras, so called because they are made up of alternate phosphor bronze and nickel plated steel filaments. This means that you get a richer acoustic response while retaining the electric sound when you want it. They sell these at Strings and beyond, and the gauges come in either 11,15,22,30,40,50 or 12,16,24,32,42,54 (which I use). Anyway, they might be worth a spin on your T5.
P.S. Sorry, Bob, I didn't read your post carefully enough. I see your question is focused on gauge, not type.